6420395820 has 96 divisors (see below), whose sum is σ = 18595100160. Its totient is φ = 1654064640.

The previous prime is 6420395819. The next prime is 6420395843. The reversal of 6420395820 is 285930246.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 240711 + ... + 266049.

It is an arithmetic number, because the mean of its divisors is an integer number (193698960).

Almost surely, 2^6420395820 is an apocalyptic number.

6420395820 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6420395820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (9297550080).

6420395820 is an abundant number, since it is smaller than the sum of its proper divisors (12174704340).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6420395820 is a wasteful number, since it uses less digits than its factorization.

6420395820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25495 (or 25493 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 39.

The square root of 6420395820 is about 80127.3724765763. The cubic root of 6420395820 is about 1858.6057130872.

The spelling of 6420395820 in words is "six billion, four hundred twenty million, three hundred ninety-five thousand, eight hundred twenty".